Uplift and shortening rates at the active front of a fold-thrust belt: Insights from the Malargüe and Chacay anticlines, southern Central Andes.

LOPASSO AILIN; FELIPE TAPIA; ROMAL LEAL ; ROBERT ONDRAK; JULIO HLEBSZEVITSCH; LAURA GIAMBIAGI; MATIAS GHIGLIONE

JOURNAL OF THE GEOLOGICAL SOCIETY

GEOLOGICAL SOC PUBL HOUSE

Lugar: Londres; Año: 2024

0016-7649

We report syntectonic sedimentation during the last deformational stages of the frontal Malargüe fold-thrust belt, recorded in progressive unconformities within foreland basin sequences yielding Miocene and Pleistocene detrital U-PB ages. Presented age determinations allow to establish a more exact upper limit to the deformation of the area. Additionally, a structural model is presented based on surface data and subsurface 2D seismic sections. The zone is characterized by a hybrid geometry with sectors with thick-skinned deformation, and zones with thin-skinned deformation styles, developed in two pulses (late Cretaceous and Miocene) of compressional deformation. Kinematic modeling was carried out to reconstruct the evolution and growth of the anticlines in the eastern sector, and the deformation of the area was quantified by calculating shortening, uplift and sedimentation rates. Our data records a wedge-top depozone active during previously proposed basin partitioning and advance of the magmatic arc and orogenic front.